Valerian
A herbal remedy traditionally used for restlessness and difficulty falling asleep.
Ventilatory equivalent
The ratio of minute ventilation to oxygen uptake or carbon dioxide output. In cardiopulmonary exercise testing its course helps determine exercise thresholds.
Ventral tegmental area
A group of dopamine-producing nerve cells in the midbrain projecting to the nucleus accumbens and frontal cortex. It is important for motivation and reward learning.
See also: Dopamine
Vertebral artery
The paired artery that runs through openings in the cervical vertebrae to the skull and joins its partner to form the basilar artery. It supplies the brainstem, cerebellum and occipital lobe; tears in its wall (dissections) can cause strokes.
See also: Circle of Willis
Vincent’s angina
A usually one-sided ulcerative tonsillitis caused by a mixed infection of fusiform bacteria and spirochaetes. Typical are painful swallowing, bad breath and an ulcer with a greasy coating, often with good general well-being.
Vitelline duct (omphalomesenteric duct)
Embryonic connection between the yolk sac and the gut that normally regresses by the 7th to 9th week. If a remnant persists, a Meckel’s diverticulum or umbilical fistula can result.